High temperature arc with method and means for preventing carbon accumulation



March 22, 1955 o MILLIE 2,704,817

HIGH TEMPERATURE A RC WITH METHOD AND MEANS FOR PREVENTING CARBON ACCUMULATION Filed Oct. 13, 1952 3 Sheets-Sheet l comwou ND FEED MECHAN SM March 22, 1955 Filed Oct. 13, 1952 O. MILLIE HIGH TEMPERATURE ARC WITH METHOD AND MEANS FOR PREVENTING CARBON ACCUMULATION 3 Sheets-Sheet 2 oooooooooo F OM All; 'MPRESSOR OR L WEJZ INVENTOR.

March 22, 1955 MILLIE 2,704,817

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Filed Oct. 13, 1952 3 Sheets-Sheet 5 230) Zgg g 5.4% TH Zgfi 230 10 INVENZOR.

United States Patent HIGH TEMPERATURE ARC WITH METHOD AND MEANS FOR PREVENTING CARBON ACCUMU- LATION Orrin Millie, New York, N. Y., assignor to Genarco, Inc., a corporation of New York Application October 13, 1952, Serial No. 314,455

Claims. (Cl. 314-) The subject matter of this invention may be used by or for the Government for governmental purposes without the payment of any royalty.

This invention relates generally to the field of electric arcs of a type used for purposes of illumination, and

more particularly to improved means for preventing the accumulation of carbon in such device in such manner as to interfere with proper operation of the same.

In the past, electric arc lights have generally been of a type in which the positive carbon is supported in a compound feed mechanism which slowly advances the same as the operative end thereof is burned away by the arc flame, so that the distance between the positive carbon and the negative carbon may be maintained substantially constant. As arc lamps are relatively large, the end of the carbon usually projects a substantial distance from the positive carbon supporting means which supplies electro-motive current to the same, and thus small particles of unburned carbon have no opportunity to collect upon the supporting surfaces of the positive carbon supporting means to interfere with the passage of current from the support means to the carbon.

In recent years, it has been found practicable to employ carbon arc lamps of a much smaller overall size, in which it is not possible to so position the feed mechanism and positive carbon that the operative end is disposed a substantial distance from the carbon support.

It has been found, however, that where the positive carbon is being consumed, a large amount of unconsumed carbon particles tend to collect in the adjacent areas. These particles, unless otherwise eliminated within a relatively short time after their formation, tend to spread and settle upon adjacent structures. Where one of the adjacent structures is the carbon support which transmits current to the positive carbon, the effect upon the operation of the lamp is quite marked.

It is therefore among the principal objects of the present invention to provide electric arc construction in which there is incorporated means for preventing the settling of carbon particles upon the positive carbon support during the operation of the same.

Another object of the invention lies in the provision of carbon arc construction of the class described in which the positive carbon is formed so as to permit the same to exert a cleansing or clearing action upon the positive carbon support as the same is advanced by the positive carbon feed mechanism.

Another object of the invention lies in the provision of air stream means which may be employed either individually or in conjunction with other means to clear away unburned carbon particles which would otherwise collect on the positive carbon support.

A further object of the invention lies in the provision of the above described structure in which the cost of incorporation into an arc lamp may be of a relatively low order, with consequent wide use and saletov the purchasing public.

A feature of the invention lies in the fact that either of the several means disclosed hereinbelow may be used either separately or in conjunction with the other means to achieve the desired result, the choice lying with the user, and dictated by actual need.

These objects and features, as Well as other incidental ends and advantages, will become more clearly apparent during the course of the following disclosure, and be pointed out in the appended claims.

On the drawings, to which reference will be made in the specification, similar reference characters have been employed to designate corresponding parts throughout the several views.

Figure 1 is a view in elevation showing an embodiment of the invention.

Figure 2 is an enlarged view in perspective showing the positive carbon rod and carbon rod support which comprise parts of the embodiment.

Figure 3 is a vertical longitudinal sectional view as seen from the plane 3-3 on Figure 2.

Figure 4 is a view in perspective showing a positive carbon rod incorporating certain features of the invention.

Figure 5 is a fragmentary view in elevation showing an alternate form of positive carbon rod.

Figure 6 is a view in elevation corresponding to that seen on Figure l, but showing a second embodiment of the invention.

Figure 7 is a view in perspective corresponding to that seen on Figure 2, but showing the second embodiment.

Figure 8 is an enlarged fragmentary view in perspective showing a third embodiment of the invention.

Figure 9 is a fragmentary vertical sectional view as seen from the plane 9-9 on Figure 10.

Figure 10 is a fragmentary vertical sectional view as seen from the plane 10-10 on Figure 9.

In accordance with the invention, the lamp into which the invention is incorporated is generally indicated by reference character 10. The lamp includes a lamp housing 12, a suitable lamp support 14, a source of electromotive energy 16, resistance means 18 for governing the flow of said energy, a compound positive carbon feed rntzlagsg 20, a positive carbon rod 22 and a negative carbon ro The positive carbon rod 22 is supported within a positive carbon rod clamp 26, the same having an upper member 28 and a lower member 30. A cylindrical bore 32 is formed in the upper and lower members 28 and 30 at the interconnection thereof, to permit the positive carbon rod 22 to be fed outwardly of the clamp 26 as the same is consumed during operation. This feeding is normally of a compound nature, that is to say the carbon rod 22 is rotated as the same is advanced, as indicated by the arrow on Figure 3.

Referring to Figure 4, it will be observed that the positive carbon rod 22 is provided with a spiral groove 34 which progresses in a direction opposite that of the rotation indicated by the'arrow on Figure 3. The spiral has a pitch substantially less than the amount of advancement traversed by the carbon through a single rotation by the compound feed means 20, so that as the carbon rod is rotated in feeding as indicated by the arrow on Figure 3 the groove will have a relative motion to the right as seen on Figure 3. The grooves are of V-shaped cross section, being formed by two side faces 36 and 38.

It has been found that where the operative end of the positive carbon rod 22 is positioned close to the positive carbon rod clamp 26, particles of unburned carbon tend to lodge within the bore 32, which if not cleared, build up to a point where they interfere with the proper operation of the lamp. By the use of positive carbon rods having a grooved outer surface, as a carbon rod is advanced, the carbon particles tend to lodge within the grooves to be pushed outwardly whereby the same may be consumed or may drop freely from the rod. 2

Referring to the alternate form of positive carbon shown on Figure 5, to avoid needless repetition, parts corresponding to those of the principal form have been designated by similar reference characters with the additional sufiix prime The alternate form of positive carbon rod 22' differs from the principal form in that the spiral groove is replaced by a series of individual grooves 34' which are spaced from each other in parallel planes. As is the case in the principal form, the carbon will collect within the grooves 34' and be expelled from the bore 32 as the carbon is advanced by the feed means 20.

Turning now to the second embodiment of the invention as shown in Figures 6 and 7, to avoid needless repetition, certain of the parts corresponding to those shown on the first embodiment of the invention have been designated by similar reference characters with the additional prefix 1.

The second embodiment of the invention differs from the first embodiment in that there is provided an air duct member 53 having a fan shaped duct 54 capable of supplying a flat stream of air indicated by the arrows 55. The duct member 53 is supplied with a continuous flow of air from a compressor or blower (not shown) through hose 51. Although the duct is shown as being positioned beneath the positive carbon rod 122, it 18 to be understood that the same may also be positioned above the same or on either side thereof, the object being to provide a continuous flow of air in a plane disposed substantially at right angles to the axis of the carbon rod.

The duct member 53 performs a dual function, in that it not only blows away particles of carbon which are brought from the bore of the clamp 126, but also prevents the same from reaching the bore as the same are emitted from the arc as the positive carbon rod is consumed. From this, it follows that the duct member 53 may be used independently of the grooved carbons shown on the drawing, it being possible to use ordinary or ungrooved carbons, although the clearing of the carbon particles will be far more effective where both the grooved carbons and the air duct are employed.

Turning now to the third embodiment of the invention as shown in Figures 8, 9 and 10, to avoid needless repetition certain of the parts corresponding to those shown on the first and second embodiment of the invention have been designated by similar reference characters with the additional prefix 2.

The third embodiment of the invention differs mm the first embodiment and second embodiment in that the flat stream of air is controlled in such a manner that the same does not actually contact the outer surface of the positive carbon rod 22, but rather the same passes very close to the outer surface to carry away particles, without providing a sufficient supply of oxygen to cause the positive carbon to burn at this point. It is to be understood that it is desirable to keep consumption of the rod at a minimum, and if too large a quantity of air is present the heated positive carbon will tend to be consumed upon coming into contact with oxygen supplied by the air stream. 7

To achieve this end the upper member 228 is formed with curvilinear passages 240 and 242 which connect with a short rectilinear passage 246. The air is supplied through passages 246 and 243 which are fed by tubes threadedly engaged therein at points 241 and 243. Thus as may be seen on Figure 9, the air enters the passages 246 and 248 to be conducted upwardly to transfer the air streams to the passages 24% and 242. These are guided in a curved path about the then upwardly disposed surface of the positive carbon 222 and out through the passage 246. At the point where the separate air streams emerging from the passages 242 and 244 meet, a small amount of turbulence takes place, and it has been found that this turbulence is particularly desirable, the same preventing the accumulation of particles immediately above the carbon in the passage, that is to say the turbulence assures that the particles are driven outwardly from the passage 246 rather than accumulating within the same.

By employing the structure shown in the third embodiment, it is possible to achieve excellent results with but very small streams of air, moving at a relatively low velocity. All of the air stream is utilized, and the tendency for the carbon rod to oxidize is kept at a minimum.

It may thus be seen that I have invented novel and highly useful improvements in electric arcs in which there is provided means for disposal of unburned carbon particles which collect in the positive carbon feed means and current supply means of the newer type compact arc lamps. The special carbon rods employed may be manufactured at a cost but slightly greater than that encountered in the manufacture of ordinary carbon, and the incorporation of air jet means to prevent the formation of carbon particles and the clearing thereof requires but a minor alteration in the construction of lamps already known in the art. The improvements are substantially trouble free in operation, and materially increase the efficiency in operation of carbon are devices of this type.

I wish it to be understood that I do not consider the invention limited to the exact details of structure shown and set forth in this specification, for obvious modifications will occur to those skilled in the art to which the present invention pertains.

I claim:

1. Electric arc construction comprising: an elongated positive carbon rod having a principal axis; a support means for said positive carbon rod having a bore in which said carbon rod is slidably disposed; and means for supplying a stream of air adjacent said support means at a direction substantially perpendicular to the principal axis thereof at the point from which the carbon rod projects from said support means; said air stream supply means including a plurality of channels adapted to direct the air in a path about the surface of said rod.

2. Electric arc construction comprising: a carbon clamp having a bore; a carbon rod disposed within said bore and having an indentation in the lateral surface thereof for receiving particles disposed within said bore; means to move said carbon rod through said bore in the direction of the are; means for exposing the clamp adjacent the area where the carbon rod projects therefrom to a current of gas; whereby the carbon rod as it is moved through the bore of the clamp collects particles from within the bore and whereby these particles are carried away by the flow of gas.

3. Electric arc construction comprising: an elongated positive carbon rod having a'principal axis; a support means for said positive carbon rod having a bore in which said carbon rod is slidably disposed; and means for supplying a stream of air adjacent said support means at a direction substantially perpendicular to the principal axis thereof at the point from which the carbon rod projects from said support means; said air stream supply means including a plurality of curved channels adgpted to direct air in a path about the surface of said ro 4; A method of producing a high temperature electric arc comprising: providing positive and negative electrodes, said positive electrode having an indentation extending into the surface of the same; striking an are between said positive and negative electrodes; advancing said positive electrode as consumed, whereby said indentation in said electrode may collectparticles; and blowing said particles from said indentation by a current of gas.

5. A method of producing a high temperature electric arc comprising: providing positive and negative electrodes, at least one of which is provided with an indentation; placing said electrodes in juxtaposition and strile mg an arc between'them; advancing said electrode having said indentation as the same is consumed whereby said indentation may'collect particles; and blowing said particles from said indentation by a current of air.

References Cited in the file of this patent UNITED STATES PATENTS 584,867 Foote June 22, 1897 1,088,296 Richards Feb. 24, 1914 1,711,983 Bassett May 7, 1929 1,783,135 Oswald Nov. 25, 1930 2,510,102 Gretener June 6, 1950 2,540,256 Gretener Feb. 6, 1951 

